drm/i915: Markup paired operations on display power domains

The majority of runtime-pm operations are bounded and scoped within a
function; these are easy to verify that the wakeref are handled
correctly. We can employ the compiler to help us, and reduce the number
of wakerefs tracked when debugging, by passing around cookies provided
by the various rpm_get functions to their rpm_put counterpart. This
makes the pairing explicit, and given the required wakeref cookie the
compiler can verify that we pass an initialised value to the rpm_put
(quite handy for double checking error paths).

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190114142129.24398-16-chris@chris-wilson.co.uk

1 files changed, 22 insertions, 14 deletions

diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index 2d6ed990a232..7f3cd055de50 100644
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -1860,12 +1860,14 @@ int intel_ddi_toggle_hdcp_signalling(struct intel_encoder *intel_encoder,
 {
 	struct drm_device *dev = intel_encoder->base.dev;
 	struct drm_i915_private *dev_priv = to_i915(dev);
+	intel_wakeref_t wakeref;
 	enum pipe pipe = 0;
 	int ret = 0;
 	uint32_t tmp;
 
-	if (WARN_ON(!intel_display_power_get_if_enabled(dev_priv,
-						intel_encoder->power_domain)))
+	wakeref = intel_display_power_get_if_enabled(dev_priv,
+						     intel_encoder->power_domain);
+	if (WARN_ON(!wakeref))
 		return -ENXIO;
 
 	if (WARN_ON(!intel_encoder->get_hw_state(intel_encoder, &pipe))) {
@@ -1880,7 +1882,7 @@ int intel_ddi_toggle_hdcp_signalling(struct intel_encoder *intel_encoder,
 		tmp &= ~TRANS_DDI_HDCP_SIGNALLING;
 	I915_WRITE(TRANS_DDI_FUNC_CTL(pipe), tmp);
 out:
-	intel_display_power_put(dev_priv, intel_encoder->power_domain);
+	intel_display_power_put(dev_priv, intel_encoder->power_domain, wakeref);
 	return ret;
 }
 
@@ -1891,13 +1893,15 @@ bool intel_ddi_connector_get_hw_state(struct intel_connector *intel_connector)
 	struct intel_encoder *encoder = intel_connector->encoder;
 	int type = intel_connector->base.connector_type;
 	enum port port = encoder->port;
-	enum pipe pipe = 0;
 	enum transcoder cpu_transcoder;
+	intel_wakeref_t wakeref;
+	enum pipe pipe = 0;
 	uint32_t tmp;
 	bool ret;
 
-	if (!intel_display_power_get_if_enabled(dev_priv,
-						encoder->power_domain))
+	wakeref = intel_display_power_get_if_enabled(dev_priv,
+						     encoder->power_domain);
+	if (!wakeref)
 		return false;
 
 	if (!encoder->get_hw_state(encoder, &pipe)) {
@@ -1939,7 +1943,7 @@ bool intel_ddi_connector_get_hw_state(struct intel_connector *intel_connector)
 	}
 
 out:
-	intel_display_power_put(dev_priv, encoder->power_domain);
+	intel_display_power_put(dev_priv, encoder->power_domain, wakeref);
 
 	return ret;
 }
@@ -1950,6 +1954,7 @@ static void intel_ddi_get_encoder_pipes(struct intel_encoder *encoder,
 	struct drm_device *dev = encoder->base.dev;
 	struct drm_i915_private *dev_priv = to_i915(dev);
 	enum port port = encoder->port;
+	intel_wakeref_t wakeref;
 	enum pipe p;
 	u32 tmp;
 	u8 mst_pipe_mask;
@@ -1957,8 +1962,9 @@ static void intel_ddi_get_encoder_pipes(struct intel_encoder *encoder,
 	*pipe_mask = 0;
 	*is_dp_mst = false;
 
-	if (!intel_display_power_get_if_enabled(dev_priv,
-						encoder->power_domain))
+	wakeref = intel_display_power_get_if_enabled(dev_priv,
+						     encoder->power_domain);
+	if (!wakeref)
 		return;
 
 	tmp = I915_READ(DDI_BUF_CTL(port));
@@ -2029,7 +2035,7 @@ out:
 				  "(PHY_CTL %08x)\n", port_name(port), tmp);
 	}
 
-	intel_display_power_put(dev_priv, encoder->power_domain);
+	intel_display_power_put(dev_priv, encoder->power_domain, wakeref);
 }
 
 bool intel_ddi_get_hw_state(struct intel_encoder *encoder,
@@ -3286,7 +3292,8 @@ static void intel_ddi_post_disable_dp(struct intel_encoder *encoder,
 	intel_edp_panel_vdd_on(intel_dp);
 	intel_edp_panel_off(intel_dp);
 
-	intel_display_power_put(dev_priv, dig_port->ddi_io_power_domain);
+	intel_display_power_put_unchecked(dev_priv,
+					  dig_port->ddi_io_power_domain);
 
 	intel_ddi_clk_disable(encoder);
 }
@@ -3306,7 +3313,8 @@ static void intel_ddi_post_disable_hdmi(struct intel_encoder *encoder,
 
 	intel_disable_ddi_buf(encoder, old_crtc_state);
 
-	intel_display_power_put(dev_priv, dig_port->ddi_io_power_domain);
+	intel_display_power_put_unchecked(dev_priv,
+					  dig_port->ddi_io_power_domain);
 
 	intel_ddi_clk_disable(encoder);
 
@@ -3626,8 +3634,8 @@ intel_ddi_post_pll_disable(struct intel_encoder *encoder,
 
 	if (intel_crtc_has_dp_encoder(crtc_state) ||
 	    intel_port_is_tc(dev_priv, encoder->port))
-		intel_display_power_put(dev_priv,
-					intel_ddi_main_link_aux_domain(dig_port));
+		intel_display_power_put_unchecked(dev_priv,
+						  intel_ddi_main_link_aux_domain(dig_port));
 }
 
 void intel_ddi_prepare_link_retrain(struct intel_dp *intel_dp)